Quantities, Units, Dimensions and Types Ontologies

QUDT Ontologies

The QUDT ontologies provide the following:

Multiple Systems of Units

Comprehensive Coverage of Quantities

Ontology Support for Units Conversion using Dimensions

Simple and Structured Data Types

The QUDT Ontologies and XML Vocabularies were developed at NASA ARC in the NExIOM project for the NASA Constellation Program. QUDT has a dedicated website at http://www.qudt.org. A table of the QUDT v1.0.0 ontologies, with generated documentation can be accessed at this page.

The qud, or quantity-unit-dimension ontology defines the base classes properties, and restrictions used for modeling physical quantities, units of measure, and their dimensions in various measurement systems.

The Units Ontology is a N1 Ontology that provides a vocabulary for describing units of measure. It also contains a limited set of individual units of measure, specifically, those units that do not have, at the moment, a dedicated N2 level ontology.

Unit Datasets

NIST Constants

Schema

Title

Details

nist

NIST Constants

Description:

Defines terms for and contains the values and standard uncertainties of 324 physical constants taken from the NIST website: The NIST Reference on Constants, Units, and Uncertainty, at http://physics.nist.gov/cuu/index.html

QUDT and DBPedia

Schema

Title

Details

qudt-dbpedia

QUDT links to DBPedia

Description:

This graph contains 823 links between terms in the QUDT ontology (quantity kinds, units, and physical constants) and their corresponding close and exact matches in DBPedia. The correspondences are stated using the properties skos:closeMatch and skos:exactMatch from the Simple Knowledge Organization System (SKOS) ontology.